Brønsted acids with weakly coordinating anions featuring group 5 metals
department or school: Science, Faculty of
department or school: Chemistry, Department of
data provider: DSpace
degree campus: UBCV
creator: Yang, Ruijie
issued: 2021-12-02T15:13:55Z
issued: 2021
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Rubber is a widely used material that plays an essential role in our daily life. However, the challenging reaction conditions make butyl rubber manufacturing very energy-intensive and difficult to control. Brønsted acids are efficient single component initiators for cationic polymerization with a simple functional cation, H⁺. The coordinating force between cations and anions is crucial for developing high-performance initiators. Weakly coordinating anions have moderate interaction force with cations. This thesis will focus on developing functional initiators containing Brønsted acids and weakly coordinating anions. The growth of the field of weakly coordinating anions has mainly relied on p-block elements such as boron, aluminum, phosphorus, and sulfur. Transition metal complexes have rarely been used as weakly coordinating anions. This thesis will show efforts on designing Ta(V)- or Nb(V)-containing steric bulky WCAs for stabilizing functional Brønsted acids. Chapters 2 and chapter 3 have shown eleven cationic initiators. Among all these cationic initiators, two of them contain anions featuring heptacoordinated Ta(V) with pentagonal bipyramid geometry. These are unprecedented Brønsted acids. H(DMF)₂[2.1] contains the [Ta(1,2-O₂C₆Cl₄)₂(1,2–O₂(OH)₂C₆Cl₄)₂(O=CHN(CH₃)₂)]– anion which has two chelated tetrachlorocatechol ligands, two monodentate tetrachlorocatechol ligands and another DMF ligand with an overall charge of was –1. In addition, [H(DMA)]₂[2.2] was isolated and crystallographically characterized. This Brønsted acid features the novel [Ta(1,2-O₂C₆Cl₄)₃(1,2– O₂(OH)₂C₆Cl₄)]²– dianion with three chelated tetrachlorocatechol and only one monodentate tetrachlorocatechol. Although not specifically tested herein, these new Brønsted acids form a foundation for the future design of novel initiators for cationic polymerization
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/80306
note: Brønsted Acids with Weakly Coordinating Anions Featuring Group 5 MetalsbyRuijie YangB.Eng. Xiamen University, 2018A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTER OF SCIENCEinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Chemistry)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)November 2021© Ruijie Yang, 2021iiThe following individuals certify that they have read, and recommend to the Faculty of Graduateand Postdoctoral Studies for acceptance, a thesis entitled:Brønsted acids with weakly coordinating anions featuring group 5 metalssubmitted by Ruijie Yang in partial fulfillment of the requirements forthe degree of Master of Sciencein ChemistryExamining Committee:Derek. Gates, Professor, Department of Chemistry, UBCSupervisorParisa Mehrkhodavandi, Professor, Department of Chemistry, UBCSupervisory Committee MemberChris Orvig, Professor, Department of Chemistry, UBCSupervisory Committee MemberiiiAbstractRubber is a widely used material that plays an essential role in our daily life. However,the challenging reaction conditions make butyl rubber manufacturing very energy-intensive anddifficult to control. Brønsted acids are efficient single component initiators for cationicpolymerization with a simple functional cation, H+. The coordinating force between cations andanions is crucial for developing high-performance initiators. Weakly coordinating anions havemoderate interaction force with cations. This thesis will focus on developing functional initiatorscontaining Brønsted acids and weakly coordinating anions.The growth of the field of weakly coordinating anions has mainly relied on p-blockelements such as boron, aluminum, phosphorus, and sulfur. Transition metal complexes haverarely been used as weakly coordinating anions. This thesis will show efforts on designingTa(V)- or Nb(V)-containing steric bulky WCAs for stabilizing functional Brønsted acids.Chapters 2 and chapter 3 have shown eleven cationic initiators. Among all these cati…
has type: Thesis/Dissertation
date issued: 2022-05
is shown at: 10.14288/1.0404418
language: eng
degree discipline: Chemistry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Gates, Derek P.
type: Text
identifier URI: http://hdl.handle.net/2429/80306